• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.4
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• pp.684-690
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• 2003

In this paper, a contention-based reservation access control algorithm and a slot allocation algorithm are proposed for non-real-time bursty traffic services in the wireless ATM networks. In order to reduce the collisions of the reservation request packets, the base station scheduler calculates the transmission probability using the number of RAS minislots and the estimated load of the reservation request packets. And it broadcasts the calculated transmission probability over the downlink control channel. Mobile terminals, which have traffic burst, select randomly a RAS minislot and transmit the reservation request packet by the received transmission probability. The reservation request packet contains the number of packets in the buffer. The slot allocation is based on the buffer status of the received reservation request packets. The base station scheduler allocates slots in proportion to the total number of slots that are requested by each terminal.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.117-120
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• 2001

In this paper, a contention-based reservation MAC protocol is proposed for non-real-time bursty traffic services in the wireless ATM networks. In order to reduce the collisions of the reservation request packets, the base station scheduler calculates the transmission probability using the number of RAS minislots and the estimated load of the reservation request packets. And it broadcasts the calculated transmission probability through the downlink control channel. Mobile terminals, which have a traffic burst, select randomly a RAS minislot and transmit the reservation request packet with the received transmission probability. The reservation request packet contains the number of packets in the buffer. The base station allocates slots based on the buffer status of the received reservation request packets.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.10
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• pp.43-50
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• 2003

This paper describes the optical resource reservation protocol for Optical Burst Switching(OBS) networks, in which the burst sending time and the burst size at an ingress node are determined by the available resources between the ingress and egress nodes. Our scheme attempts to improve the burst contention resolution and optical channel utilization. We analyze the performance of the optical resource reservation protocol by using NS2 simulator.

• Journal of Korea Multimedia Society
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• v.7 no.3
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• pp.357-367
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• 2004

In VOD systems the number of channels available to a video server is limited since the number of channels, the video server can support, is determined by the communication bandwidth of the video server. Multicast techniques such as batching, patching and batch-patching have been proposed to reduce I/O demand on the video server by sharing multicast data. In this paper, we propose a channel reservation batch-patching technique that first applies the batching technique to hot video requests and then applies the patching technique to the batches of the hot video requests. And the proposed technique reserves a part of the channel capacity of the video server for many hot video requests, so that the hot video requests can be served without defection. The performance of the proposed technique is compared with those of Patching and Batch-Patching techniques in terms of average service latency, defection rate, fairness and frame reduction rate by simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.3B
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• pp.191-199
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• 2003

In this paper, a channel access control algorithm and a dynamic slot allocation algorithm are proposed for rt_VBR services and ABR services in the wireless ATM networks. In the proposed algorithm, rt_VBR terminals that require real-time services transmit a reservation request packet by a RAS minislot. An rt_VBR terminal, which transmitted the reservation request packet, transmits the dynamic parameters by DPS minislot without contention. On the other hand, ABR terminals that have a non-real-time traffic burst transfer a reservation request packet with contention basis. Based on the received dynamic parameters, the base station scheduler allocates uplink data slots as well as DPS minislot into rt_VBR terminals.

• Journal of Korea Multimedia Society
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• v.15 no.12
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• pp.1464-1474
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• 2012

In this paper, we propose a QoS (Quality of Service)-aware and cooperative resource reservation scheme using cross-layer link adaptation for wireless high definition video transmission through UWB (Ultra Wide Band) network with D-MAC (Distributed Medium Access Control). A wireless high definition video transmission system usually requires stable high throughput even without line-of-sight, e.g., a destination device in another room separated by a wall. Since the WiMedia D-MAC supporting DRP (Distributed Reservation Protocol) scheme causes lots of DRP resource reservation conflicts due to failure of beacon detection in wireless channel environment, overall performances of the WiMedia D-MAC can be deteriorated. And the current WiMedia MAC standard has not considered QoS provisioning even though QoS parameters such as a range of service rates are provided to each traffic stream. Therefore, we propose Relay DRP protocol with QoS-based relay node selection criterion, which makes a relay path to avoid DRP resource reservation conflicts and guarantee QoS more stably through cross-layer link adaptation of cooperative relay transmission scheme and is compliant with the current WiMedia D-MAC protocol. Simulation results demonstrate performance improvements of the proposed method for throughput and QoS provisioning.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.1
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• pp.16-27
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• 2012

In multi-interface multi-channel(MIMC) based tactical ad hoc networks, QoS support for required operational capacity is one of the main challenging issues for multi-hop transmissions. To support QoS in such a harsh environment, we propose a novel MAC scheme to minimize multi-hop as well as per-hop delay. The current IEEE 802.11 MAC protocols should contend to reserve the channel resource at every hop by each sender. The every-hop channel contention results in a degradation of end-to-end delay for multi-hop transmissions. The basic idea of our scheme is to make a "multi-hop reservation" at the MAC layer by using the modified RTS frame. It contains additional information such as destination information, packet priority, and hop count, etc. In addition, we differentiate the contention window area according to the packet priority and the number of hops to deliver packets in the predefined allowed latency. Our scheme can minimize the multi-hop delay and support the QoS of the critical data in real time(i.e., VoIP, sensing video data, Video conference between commanders). Our simulation study and numerical analysis show that the proposed scheme outperforms the IEEE 802.11 MAC.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.2A
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• pp.143-151
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• 2007

One of the consideration things to design protocol in wireless sensor networks is to maximize lifetime of sensor node as reducing energy consumption. In this paper propose reserve based multichannel CSMA mac protocol for minimizing energy consumption which arise from collision and waiting retransmission at channel access process in mac layer Each sensor node which constitute sensor networks has data channel and control channel. And as sensor node reserve channel for data transmission by using control channel and receipt node allow reservation node to use data channel, sending node can abbreviate try of retransmission after random interval time. Also, When sending node delivers selects option channel in available channels to receipt node, the receipt node decide whether the channel is available to oneself and through the result select transmission channel ultimately. Performance evaluation compare with previous simple multichannel CSMA.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.3B
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• pp.423-430
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• 2000

Future microcellular systems will require distributed network control. A packet-switched network is suitable for this requirement. The packet reservation multiple access(PRMA) is a Reservation-ALOHA like protocol for wireless terminals to transmit packet speech to a base station. It allows spatially distributed users in cellular systems to transmit packeted voice and data to a common base station using a shared channel. In the existing PRMA, the problem is that the voice packets may collide with the data packets due to simultaneous channel access. the problem may be a major performance degradation factor to a voice and data mixed system. We propose a new PRMA method that integrates voice and data traffic efficiently by resolving the collision problem between data and voice packets. The proposed PRMA method gives a performance improvement than the existing PRAMA method in terms of voice packet dropping probability and data delay characteristic. From analytic results, we can confirm that the proposed PRMA method show a performance improvement than the existing PRMA protocol.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.457-459
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• 2005

OBS(Optical Burst Switching) 망에서 우선 순위를 보장해 주기 위해 채널 선정 방식(preemptive channel reservation scheme)이 제안되어 왔다. 채널 선점으로 인해 drop된 버스트의 크기가 OBS 망의 전체 성능에 영향을 끼치는 요소인데도 불구하고 기존의 채널 선점 방식은 선점될 채널 선택 시에 버스트의 채널 사용 시간(elapsed time)만을 고려하고 있다. 따라서 본 논문에서는 각 버스트의 채널 사용 시간과 버스트 길이의 합이 작은 채널을 선택하는 선점 방식으로써 Length-based Smallest Elapsed time Selection(LSE)을 제안한다 시뮬레이션을 통하여 제안하는 LSE 방식이 기존의 SE(Smallest Elapsed time)에 비해서 버스트 손실 성능 면에서 우수함을 알 수 있었다.